Heat is defined as the measure of the amount of thermal or kinetic energy in a body. Heat transfer is therefore the movement of the kinetic energy from one part of the body to another. This movement is usually due to a temperature gradient brought about by a difference in temperature between the two points (the heat moving from the area of higher temperature to lower temperature). Heat transfer occurs until the body and it surroundings achieve thermal equilibrium (Incropera & DeWit 76).
The three main modes by which heat is transferred are conduction, convection and radiation. In Conduction, heat is transferred by contact of molecules from the two points between which heat transfer is occurring. Adjacent particles vibrate and transfer kinetic energy to each other while transferring heat; this then implies that heat transfer by conduction would be a lot higher in solids than in fluids. This is attributed to the fact that particles in solids are very closely packed making contact very easy. Liquid and gas particles on the other hand have their particles more widely spaced making heat transfer by conduction less dominant (Incropera & DeWit 76).
In heat transfer by convection, heat is transferred by movement of a part of the fluid which mixes with another part of the fluid transferring heat to it. The faster the fluid moves, the faster the heat transfer. Convective heat transfer can occur in two modes: natural and forced convection. Natural convection occurs when the fluids move naturally due to changing density brought about by temperature differences. Forced convection on the other hand is manifested when the fluids are forced to flow by employing heat pumps (Incropera & DeWit 77).
Heat transfer by radiation occurs in space and therefore does not require a medium of transfer. This is the way by which the sun’s energy reaches the earth through space. The heat is transferred by electromagnetic waves (Incropera & DeWit 76).
Heat transfer through walls is very fundamental in Engineering, particularly in the construction industry. The study of Heat transfer through walls enables engineers to design thermally sound structures. Dwellings, controlled environments and offices all need proper ventilation and air conditioning which can only be achieved with proper knowledge of heat transfer principles.
Heat transfer through walls is of special importance to civil engineers in temperate regions where temperature ranges are very wide, with winters getting below 0 degrees Celsius and summers over 40 degrees. Heat transfer principles help designers build houses that can withstand these extreme conditions while ensuring comfort for the dwellers. Controlled environments such as operating theaters also have very specific ambient environment requirements due to their high sensitivity. Heat transfer then becomes vital as it helps design walls that can help keep the environment just right. Choice of colors for these buildings is also an important issue that can affect the thermal properties of the building; this can easily be properly decided upon thorough study of heat transfer through walls, which discusses their thermal properties. Heat transfer could also be interrelated with other disciplines and lead to breakthroughs in areas such as food production. Green houses have been a very successful means of ensuring continuous food production in temperate regions. Heat transfer through walls has been very instrumental in these areas as the green houses must be maintained at the right temperatures for optimum production. This can only be achieved by building properly designed walls to ensure this through in depth consideration of heat transfer through walls’ principles.
The study of heat transfer through walls is therefore vital in many aspects of our lives both n terms of economics and production. It can also be used in collaboration with other disciplines to find solutions for problems of global concern like food security.
Works cited
Incropera, Frank and DeWitt, David. Fundamentals of Heat and Mass Transfer, 5th Edition. New York: Publishers, 2005.